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The bones in your back are called your spine. Your spine holds your body upright and lets you twist and bend. It also protects the bundle of nerves running from your brain down to all the rest of your body called the spinal cord. There are 26 bones, called vertebrae, in your spine. Attached to the back of your spine are your ribs. Most people have twelve sets of ribs, twelve bones on the right side of the body, and twelve on the left. Your ribs protect your heart, lungs, and liver.